Cutting insert with internal cooling, mold and method for manufacture thereof

ABSTRACT

A cutting insert is provided, comprising a top surface, a bottom surface, a plurality of side surfaces spanning therebetween, and a cutting edge formed at an intersection of the side surface and a forwardly-disposed portion of the top the surface. It further comprises a cooling cavity projecting into the insert, a top end thereof being disposed further forwardly than an open bottom end thereof. The cooling cavity defines at least one molding axis such that a solid element having the shape of the cooling cavity and completely inserted therein may be retracted intact therefrom along a linear path parallel to the molding axis. A circumscribing portion is formed on the side surfaces encircling the cutting insert. The circumscribing portion is formed parallel to the molding axis and has a non-zero height along its entire extent. The cutting insert does not extend beyond the circumscribing portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/160,746 filed on Oct. 15, 2018, which is a continuation-in-part ofU.S. application Ser. No. 14/901,514 filed Dec. 28, 2015, which is aU.S. National Phase Application filed under 35 U.S.C. § 371 of PCTInternational Application No. PCT/IL2014/050573 filed Jun. 26, 2014,which claims priority to Israel Patent Application No. 227228 filed Jun.27, 2013, the contents of all of the foregoing applications areincorporated herein by reference in their entireties.

TECHNOLOGICAL FIELD

The present invention relates to cutting tools and inserts having aninternal cooling mechanism.

BACKGROUND

It is known in the art to provide a cooling fluid to a cutting interfacebetween a cutting tool and a workpiece during a cutting operation. Theprovision of the cooling fluid allows reducing the heat generated at thecutting interface during the cutting operation and thereby preventingdamage to both the cutting edge and the workpiece.

In general, a cutting tool has a rake face and a relief face, definingat the intersection thereof a cutting edge of the cutting tool. Coolingfluid is generally provided directly to the cutting interface eitherfrom the side of the rake face or from the side of the relief face orfrom both.

In some examples, cutting inserts used in cutting tools are pre-formedwith apertures configured for the provision of a cooling fluid. In otherexamples, cutting tools and/or cutting tool holders are provided with acooling arrangement separate from the cutting insert, which isconfigured for provision of the cooling fluid.

SUMMARY

According to one aspect of the presently disclosed subject matter, thereis provided a cutting insert comprising:

-   -   a top surface, a bottom surface, and a plurality of side        surfaces spanning therebetween;    -   a cutting edge formed at an intersection of the side surface and        a forwardly-disposed portion of the top the surface;    -   a cooling cavity projecting into the insert and spanning between        an open bottom end formed in the bottom surface and a top end,        the top end of the cooling cavity being disposed further        forwardly than a forward-most portion of the bottom end thereof,        the cooling cavity defining one or more molding angles, with        respect to the bottom surface, along which a molding axis may        lie, wherein a solid element having the shape of the cooling        cavity and completely inserted therein may be retracted intact        therefrom along a linear path parallel to the molding axis; and    -   a circumscribing portion formed on the side surfaces and        encircling the cutting insert, wherein the circumscribing        portion is formed parallel to the molding axis and has a        non-zero height, in a direction parallel to the molding axis,        along its entire extent, and wherein the cutting insert does not        extend beyond the circumscribing portion.

The circumscribing portion may be continuous around the cutting insert.

The molding axis may be disposed at an angle of 45° with respect to thebottom surface.

The top and bottom surfaces may be parallel to each other.

The height of the circumscribing portion may vary along its extent.

At least one of the side surfaces may comprise a shelf extending alongat least a portion of its length, the shelf defining a plane transverseto the molding axis and facing an area free of material of the cuttinginsert along any path parallel to the molding axis and intersecting theshelf.

The shelf may generally face towards the top surface.

At least two adjacent side surfaces may comprise a shelf.

The cutting insert may further comprise a second cooling cavity formedon an opposite side thereof, the second cooling cavity being formedcorrespondingly to the cooling cavity and inverted with respect thereto,and disposed such that it is open to the top surface.

According to another aspect of the presently disclosed subject matter,there is provided a mold for producing the cutting insert as per theabove, the mold comprising a female mold portion and a male moldportion,

-   -   the female mold portion comprising a cavity defined between        parallelly extending sidewalls and an open top end, and an        upwardly facing first imprinting surface formed on a bottom end        of the cavity;    -   the male mold portion being configured to be snuggly and        slidably received within the cavity of the female mold portion,        and comprising a downwardly facing second imprinting surface;    -   wherein the first imprinting surface has a shape corresponding        to that of a first part of the cutting insert, when oriented        such that its molding axis is parallel to the sidewalls of the        female mold portion, demarcated by a first edge of the        circumscribing portion, and the second imprinting surface has a        shape corresponding to that of a second part of the cutting        insert, when oriented such that its mold axis is parallel to the        sidewalls of the female mold portion, demarcated by a second        edge of the circumscribing portion.

According to a further aspect of the presently disclosed subject matter,there is provided a method of manufacture of a cutting insert as per theabove, the method comprising:

-   -   providing a mold according to as per the above;    -   providing raw material in the cavity of the female mold portion;    -   inserting the male mold portion into the cavity such that the        first and second imprinting surfaces face one another; and    -   forming the cutting insert, from the raw material, in the space        between the imprinting surfaces.

The raw material may be a sintering material, the forming comprisingproviding sufficient pressure along the molding axis to form the insertfrom the sintering materiel.

The sintering material may comprise a ceramic powder.

The raw material may be provided in liquefied form, the formingcomprising allowing the raw material to solidify.

According to a still aspect of the presently disclosed subject matter,there is provided a cutting insert comprising: a front face, an oppositerear face and at least one side face extending therebetween, saidcutting insert comprising: a cooling cavity formed therein comprising acavity surface and having an open end formed in the rear face of thecutting insert, and at least one shell-like cutting zone defined by anexternal surface and an internal surface, the external surface beingconstituted by a cutting edge defined at the intersection between thefront face and the at least one side face and corresponding rake andrelief surfaces constituted by portions of the front fact and at leastone side face respectively, and the internal surface being constitutedby a portion of the cavity surface, wherein the portion of the cuttingzone between the cavity surface and the external surface at the cuttingzone comprises a thin-walled structure, said cooling cavity beingconfigured for receiving therein, via the open end, a cooling fluid forcooling said inner surface and thereby withdrawing heat from the cuttingedge, and being further configured for directing the cooling fluidtowards the open end for being emitted therefrom.

The term “shell-like” refers to the fact that the cutting zone is formedof a relatively thin shell owing to a hollow structure of the cuttinginsert. In particular, a through-thickness of the thickest portion ofthe thin-walled structure and the distance between the front face andits opposing rear face can be in the range of 1:5 to 1:10.

More specifically, the through-thickness of the thickest portion of thethin-walled structure ranges between 0.2-1 mm, more particularly between0.3-0.9 mm, even more particularly between 0.4-0.8 mm and still moreparticularly between 0.5-0.7 mm.

It will be appreciated that herein the specification and appendedclaims, descriptions and/or recitations of a thin-walled structurebetween the cavity surface and the external surface at the cutting zoneof the cutting insert (and other similar descriptions/recitations e.g.,as clear from context) clearly convey to one having skill in the art aconstruction of the cutting insert in which the amount of materialbetween the cavity and the external surface of the cutting insert issmall enough such that introduction of a cooling medium, such as aliquid, gas, combination thereof, etc., into the cavity during a cuttingoperation significantly reduces the temperature of the cutting insert,for example in the vicinity of the cutting edge. The significance of thetemperature reduction may be, e.g., such that the useful life of thecutting insert is increased thereby at least as much as it would bereduced owing to any loss in structural integrity which may result fromproviding a thin-walled structure in the vicinity of the cutting edge.For example, the thickness of the thin-walled structure, e.g., between atop cavity surface distal from the open end of the cavity and thecutting edge and/or between the at least one side surface and a frontsurface of the cavity proximate to the at least one side surface, may beno greater than half the height (i.e., the distance between the frontand rear opposing surfaces of the cutting insert. According to someexamples, it is no greater than one third. According to other examples,it is no greater than one quarter, one fifth, one tenth, or even less,of the height of the cutting insert.

According to one example, the cavity surface can be sloped towards thecutting zone in order to direct cooling fluid entering the cavitytowards the cutting zone. The arrangement can be such that, inoperation, cooling fluid entering the cavity is configured to impact thesloped cavity surface and directed to flow towards the cutting zone soas to cool down the cutting edge from its internal side.

According to one design embodiment, the cavity surface can be formedwith a rib array extending along the cutting zone. In particular, saidrib array can comprise rake ribs extending generally parallel to therake surface and relief ribs extending generally parallel to the reliefsurface.

The ribs of the rib array can provide, inter alia, at least one of thefollowing:

-   -   increased mechanical integrity (i.e., strength) to the cutting        zone despite its shell-like configuration; and    -   increased in surface area for increased heat dissipation        (thereby leading to increased cooling) of the cutting edge.

In particular, it is appreciated that the ribs provide the shell-likestructure of the cutting zone, which is considerably thinner than in astandard, non-hollow insert (full of material at the cutting zone) withthe required mechanical integrity to withstand the loads exerted on thecutting insert during a cutting operation.

It is also appreciated that the jagged design of the ribs yields thatsome points of the cavity surface are closer to the cutting edge thanothers. Thus, while the average shell-thickness can be T (an average ofthe distances of all points on the cavity surface at the cutting zonefrom the cutting edge), some points along the cavity surface at thecutting zone are extremely close to the cutting edge, with a thicknesst<T. This provides for considerable efficiency in the cooling of thecutting edge without deteriorating mechanical integrity of the cuttingzone.

In other words, in a corresponding structure having a smoother cavitysurface at the same average thickness T, the cooling efficiency would belesser than in the above described example and the mechanical integritymay be lesser as well.

The arrangement can be such that the cooling fluid provided to thecavity is configured for cooling the cutting edge from the side of thecavity surface. In particular, cooling fluid provided into the coolingcavity is configured, by virtue of the geometry of the cavity so as notto come into direct contact with the cutting edge.

In some examples, there is at least one of a single rake rib and asingle relief rib, i.e., each array if present comprises at least onerib. The rake rib or relief rib may be located centrally, e.g.,symmetrically within the cavity, or may be located off-center, i.e.,asymmetrically. The selection of location of the one or more ribs can besuch as to optimize the provision of both cooling and strengthening ofthe cutting insert. Thus, for example, the provision of one or more ribsin an asymmetric manner may sufficiently strengthen the cutting insert,while ensuring also that the cooling medium can reach a major portion ofthe cavity proximate to the cutting edge, which can significantly reducethe temperature of the cutting insert in particular at the cutting edge.The significance of the temperature reduction may be, e.g., such thatthe useful life of the cutting insert is increased thereby at least asmuch as it would be reduced owing to any loss in structural integritywhich may result from providing only a single rib asymmetrically on thethin-walled structure in the vicinity of the cutting edge. According tosome examples, providing the rake and/or relief rib off-center may beuseful wherein during use, an off-center portion of the cutting insertcontacts the workpiece to perform the operation; accordingly, forexample, the increased mechanical strength and/or surface area for heatdissipation may be provided as close as possible to the portion of thecutting edge engaged in the cutting operation.

According to one example, each cutting edge of the cutting insert canhave a corresponding cooling cavity. Alternatively, the majority of saidcutting insert can be hollow, comprising a single cooling cavityfacilitating cooling for all cutting edges of the cutting insert.

In addition, it is appreciated that, on the one hand, the smaller theheight of the cutting insert (i.e., the distance between the front faceand the rear face), the stronger the cutting insert since the cuttingedge is elevated over a smaller hollow area. On the other hand, thelesser the height of the cutting insert, the lesser the space forcooling fluid to flow. Thus, the geometry of the cutting insert and ofthe cavity can be such that meet the required cooling on the one handwhile meeting mechanical integrity requirements on the other.

In particular, the following differences should be noted betweendifferent cutting operations:

Milling—

the cutting edge keeps coming in and out of contact with the workpiece.As a result, when it is in contact with the workpiece the cutting edgeheats up, whereas when it is out of contact, the cutting edge coolsdown. However, this constant motion in and out of the workpiece causesthe milling insert to be repeatedly “impacted” by the workpiece,requiring sufficient mechanical robustness and stability. In such case,it may be beneficial to provide a more robust structure of the cuttinginsert by using a configuration in which each cutting zone is providedwith its individual cooling cavity;

Turning—

the cutting edge remains within the workpiece throughout the cuttingoperation, whereby the effect of “impact” by the workpiece, which occursin milling, is eliminated. However, since the cutting edge is constantlyin contact with the workpiece, it constantly heats up, requiringsufficient cooling to prevent mechanical damage to the cutting insert.

In addition, the front face of the cutting insert can be formed with atleast one drainage outlet being in fluid communication with the coolingcavity, and wherein the drainage outlet is arranged such that coolingfluid discharged therethrough does not come in contact with the cuttingedge.

According to a still aspect of the presently disclosed subject matter,there is provided a cutting tool comprising:

-   -   a cutting tool holder comprising an insert seat space defined        between a base surface provided with a fluid inlet for providing        cooling fluid to the insert seat space and a fluid outlet        configured for removing cooling fluid from the insert seat        space; and    -   a cutting insert according to any one of Claims 1 to 8        positioned within the insert seat space of the cutting tool        holder, over the base surface;

wherein, a cooling cavity of the cutting insert is aligned with saidinlet and said outlet, whereby cooling fluid is configured for beingprovided into the cooling cavity via said inlet and be withdrawntherefrom via said outlet.

In reference to the above, the base surface can be provided with a rampelement configured, when the cutting tool is assembled and the cuttinginsert is mounted onto the base surface, to protrude into the cavity ofthe cutting insert to thereby define a fluid path. Specifically, thefluid path can be configured for receiving cooling fluid through saidinlet, directing it towards the portion of the cavity surface at thecutting zone and then towards said outlet. According to a specificexample, the cross-sectional area of the fluid path can decrease towardsthe cutting zone.

According to one design, the base surface can be unitary with thecutting tool holder. Alternatively, according to another design, thecutting tool holder can comprise an intermediate base plate formed withsaid base surface.

The intermediate base plate can be provided with an inlet bore alignedwith the inlet of the cutting tool holder and the cooling cavity of thecutting insert and an outlet bore aligned with the outlet of the cuttingtool holder and the cooling cavity of the cutting insert, to allowpassage of cooling fluid therethrough.

The cutting tool can be a milling tool comprising a plurality of cuttinginserts mounted thereto, wherein said outlet has an open end at a rearportion of the insert seat space, so as to direct cooling fluiddischarged from the outlet towards a subsequent cutting insert of themilling tool.

According to a still aspect of the presently disclosed subject matter,there is provided a cutting tool holder for mounting thereon a cuttinginsert to form a cutting tool, said cutting tool holder comprising aninsert seat space having a base surface onto which said cutting insertis to be mounted, said base surface being provided with a fluid inletfor providing cooling fluid to the insert seat space and a fluid outletconfigured for removing cooling fluid from the insert seat space.

In addition, the following points should be noted:

-   -   the cutting insert can be manufactured by a pressing process        within a mold, simplifying production thereof;    -   more efficient cooling of the cutting zone of a cutting insert        can provide at least one of the following advantages: longer        life span of the cutting insert under standard cutting        conditions, an increased feed and/or increased revolution speed        of the cutting tool or of a corresponding workpiece, thereby        reducing the required time for performing a predetermined        cutting operation;    -   the cooling fluid can be any know cooling fluid including water,        air, nitrogen etc.; and    -   producing the cutting insert with a cavity saves valuable        material (e.g., tungsten carbide).

The cavity of the cutting insert can be formed at an angle to thecutting edge. In particular, it can be angled at 45° to a top or bottomsurface of the cutting insert. The insert bore, in turn, can be angledto a top and bottom surface thereof and configured for receiving thereina fastening member in a direction generally perpendicular to the top andbottom surface.

The cutting insert can have a first portion and a second portion, angledat about 135° with respect to each other.

The cutting insert can comprise a flow channel at the top surfacethereof, configured for concentrating fluid flow towards the cuttingedge. An outlet of the flow channel can be located below the topsurface, and a top surface of the cutting insert can be of angledconfiguration while a bottom surface thereof is generally flat.

The cutting insert can be configured for performing a drilling operationor mounting onto a tool holder to form a drilling tool configured forperforming a drilling operation.

Specifically, the drilling insert can comprise an outlet configured foremitting a cooling fluid to cool the cutting edge, wherein cooling isaided by centrifugal forces caused by rotation of the drilling toolitself.

In effect, centrifugal forces facilitate emission of the cooling fluidtowards the cutting edge while rotation of the drilling tool withrespect to a bottom surface of the workpiece allows the workpiece toremove cooling fluid away from the cutting edge.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to better understand the subject matter that is disclosedherein and to exemplify how it may be carried out in practice,embodiments will now be described, by way of non-limiting example only,with reference to the accompanying drawings, in which:

FIG. 1A is a schematic isometric view of a cutting tool according to thesubject matter of the present application;

FIG. 1B is a schematic exploded isometric view of the cutting tool shownin FIG. 1B;

FIG. 2 is a schematic isometric view of a tool holder used in thecutting tool shown in FIGS. 1A and 1B;

FIG. 3 is a schematic isometric view of a base plate used in the cuttingtool shown in FIGS. 1A and 1B;

FIG. 4 is a schematic enlarged view of the base plate of FIG. 3 whenmounted onto the tool holder of FIG. 2;

FIG. 5A is a schematic bottom isometric view of a cutting insert used inthe cutting tool shown in FIGS. 1A and 1B;

FIG. 5B is a schematic isometric section view of the cutting insertshown in FIG. 5A;

FIG. 6 is a schematic section view of a portion of the cutting toolshown in FIGS. 1A and 1B;

FIG. 7A is a schematic exploded isometric view of a mold for themanufacture of the cutting insert shown in FIGS. 5A and 5B;

FIG. 7B is a schematic enlarged isometric view of a male part of themold shown in FIG. 7A;

FIG. 8A is a schematic isometric view of a cutting tool according toanother example of the subject matter of the present application;

FIG. 8B is a schematic bottom isometric view of the cutting tool shownin FIG. 8A;

FIG. 8C is a schematic exploded isometric view of the cutting tool shownin FIG. 8A;

FIG. 9A is a schematic isometric view of a cutting tool according toanother example of the subject matter of the present application;

FIG. 9B is a schematic exploded isometric view of the cutting tool shownin FIG. 9A;

FIG. 9C is a schematic isometric view of the cutting tool shown in FIG.9A, demonstrating the flow of a cooling fluid;

FIG. 9D is a schematic isometric view of the cutting tool shown in FIG.9, with a cutting insert thereof being removed;

FIG. 10 is a schematic bottom isometric view of the cutting insert shownin FIG. 9C;

FIG. 11 is a schematic section view of the cutting tool shown in FIG.9A;

FIG. 12 is a schematic isometric view of a cutting tool according tostill another example of the subject matter of the present application;

FIG. 13A is a schematic isometric view of a cutting insert used in thecutting tool shown in FIG. 12;

FIG. 13B is a schematic bottom isometric view of the cutting insertshown in FIG. 13A;

FIG. 14 is a schematic isometric view of a male part of a mold for themanufacture of the cutting insert shown in FIG. 13B;

FIG. 15A is a schematic isometric view of a milling tool according toanother example of the subject matter of the present application;

FIG. 15B is a schematic enlarged view of an insert seat space of themilling tool shown in FIG. 15A;

FIG. 15C is a schematic isometric view of the insert seat space shown inFIG. 15B, demonstrating the flow of a cooling fluid;

FIG. 15D is a schematic isometric section view of the milling tool shownin FIG. 15A, demonstrating the flow of cooling fluid;

FIG. 16A is a schematic isometric view of a milling insert used in themilling tool shown in FIG. 15A;

FIG. 16B is a schematic bottom isometric view of the milling insertshown in FIG. 16A;

FIG. 17A is a schematic exploded isometric view of a mold for themanufacture of the milling insert shown in FIGS. 16A and 16B;

FIG. 17B is a schematic isometric view of a male part of the mold shownin FIG. 17A;

FIG. 18A is a schematic isometric view of a cutting tool according tostill another example of the subject matter of the present application;

FIG. 18B is a schematic top isometric view of a cutting insert used inthe cutting tool shown in FIG. 18A;

FIG. 18C is a schematic bottom isometric view of the cutting insertshown in FIG. 18B;

FIG. 18D is a schematic side view of the cutting insert shown in FIG.18B;

FIG. 18E is a top plan view of the cutting insert shown in FIG. 18B,perpendicular to axis M illustrated in FIG. 18D;

FIG. 18F is a side view of the cutting insert shown in FIG. 18B, viewedas indicated by arrow I in FIG. 18D;

FIG. 18G is a side view of the cutting insert shown in FIG. 18B, viewedas indicated by arrow II in FIG. 18D;

FIG. 19 is a schematic isometric section view of the cutting tool shownin FIG. 18A, taken along plane I-I shown in FIG. 18A, demonstrating theflow of cooling fluid;

FIG. 20A is a schematic exploded isometric view of a mold for themanufacture of the cutting insert shown in FIGS. 18B and 18C;

FIG. 20B is a schematic isometric view of a male mold portion of themold shown in FIG. 20A;

FIG. 20C is a schematic section view of a female mold portion of themold shown in FIG. 20A;

FIG. 20D illustrates a method of forming the cutting insert shown inFIG. 18B, using the mold illustrated in FIG. 20A;

FIG. 21A is a schematic isometric view of a cutting tool according tostill another example of the subject matter of the present application;

FIG. 21B is a schematic isometric view of the cutting tool shown in FIG.21A, with a cutting insert thereof being removed;

FIG. 21C is a schematic exploded isometric view of the cutting toolshown in FIG. 21A;

FIG. 22A is a schematic isometric view of a cutting insert used in thecutting tool shown in FIG. 21A;

FIG. 22B is a schematic front view of a cutting insert used in thecutting tool shown in FIG. 21A;

FIG. 22C is a schematic top view of a cutting insert used in the cuttingtool shown in FIG. 21A;

FIG. 22D is a schematic side view of a cutting insert used in thecutting tool shown in FIG. 21A;

FIG. 23 is a schematic isometric longitudinal section view of thecutting tool shown in FIG. 21A;

FIG. 24A is a schematic exploded isometric view of a mold for themanufacture of the cutting insert shown in FIGS. 22A-22D;

FIG. 24B is a schematic isometric enlarged view of a male part of themold shown in FIG. 24A;

FIG. 24C is a schematic section view of a female part of the mold shownin FIG. 24A;

FIG. 25A is a schematic isometric view of a cutting tool according tostill another example of the subject matter of the present application;

FIG. 25B is a schematic enlarged view of detail N of the cutting toolshown in FIG. 25A;

FIG. 25C is a schematic isometric longitudinal section view of thecutting tool shown in FIG. 25A, demonstrating the flow of cooling fluid;

FIG. 25D is a schematic isometric view of the cutting tool shown in FIG.25A, with a cutting insert thereof being removed;

FIG. 25E is a schematic exploded isometric view of the cutting toolshown in FIG. 25A;

FIG. 26A is a schematic bottom view of a cutting insert used in thecutting tool shown in FIG. 25A;

FIG. 26B is a schematic side view of a cutting insert used in thecutting tool shown in FIG. 25A;

FIG. 27 is a schematic enlarged view of the cutting insert shown in FIG.26A, with a cutting insert thereof being removed, demonstrating the flowof cooling fluid;

FIG. 28 is a schematic isometric view of a cutting tool according tostill another example of the subject matter of the present application;

FIG. 29A is a schematic side view of a cutting insert used in thecutting tool shown in FIG. 28;

FIG. 29B is a schematic side view of a cutting insert, demonstrating thedifferences between the cutting insert shown in FIGS. 26B and 29A;

FIG. 30A is a schematic isometric view of a cutting tool according tostill another example of the subject matter of the present application;

FIG. 30B is a schematic exploded isometric view of the cutting toolshown in FIG. 30A;

FIG. 31A is a schematic isometric view of a cutting insert used in thecutting tool shown in FIG. 30A;

FIG. 31B is a schematic isometric section view of the cutting tool shownin FIG. 30A, demonstrating the flow of cooling fluid;

FIG. 31C is a schematic section view of the cutting tool shown in FIG.30A, demonstrating the cutting insert's fastening mechanism;

FIG. 32 is a schematic isometric view of a cutting tool according tostill another example of the subject matter of the present application;

FIG. 33A is a schematic top view of a cutting insert used in the cuttingtool shown in FIG. 32;

FIG. 33B is a schematic side view of a cutting insert used in thecutting tool shown in FIG. 32;

FIG. 33C is a schematic isometric enlarged view of a cutting insert usedin the cutting tool shown in FIG. 32;

FIG. 34A is a schematic isometric view of a milling tool according tostill another example of the subject matter of the present application;

FIG. 34B is a schematic enlarged view of the milling tool shown in FIG.34A;

FIG. 35A is a schematic enlarged view of an insert seat space of themilling tool shown in FIG. 34A;

FIG. 35B is a schematic isometric section view of the milling tool shownin FIG. 34A, demonstrating the flow of cooling fluid;

FIG. 36A is a schematic isometric view of a milling insert used in themilling tool shown in FIG. 34A;

FIG. 36B is a schematic top view of the milling insert shown in FIG.36A;

FIG. 36C is a schematic bottom view of the milling insert shown in FIG.36A;

FIG. 36D is a schematic view of the milling insert shown in FIG. 36A;

FIG. 36E is a schematic side view of the milling insert shown in FIG.36A;

FIG. 37A is a schematic isometric view of a drilling tool according tothe subject matter of the present application;

FIG. 37B is a schematic enlarged view of the drilling tool shown in FIG.37A;

FIG. 38 is a schematic isometric section view of the drilling tool shownin FIG. 37A, demonstrating the flow of cooling fluid;

DETAILED DESCRIPTION

As illustrated in FIGS. 1A and 1B, a cutting tool according to thepresently disclosed subject matter, generally designated as 1, comprisesa tool holder 10, a base plate 30 (for example made of widia), a cuttinginsert 50, a securing bolt 70 for clamping the cutting insert to thetool holder, and an auxiliary securing bolt 80 for clamping the baseplate to the tool holder, below the cutting insert. As will be describedherein below, the cutting tool 1 is designed so as to allow cooling ofthe area of the cutting edge thereof during a cutting, e.g., a turning,operation.

As seen in FIG. 2, the cutting tool holder 10 comprises a main body 12formed with an insert seat space 20 for mounting thereon the base plate30 and the cutting insert 50. The body 12 is provided with a coolingfluid provision channel 16 passing therethrough and configured forproviding a cooling fluid to the insert seat space 20. The insert seatspace 20 is defined between a bottom face 22, configured for positioningthereon of the base plate 30, and, e.g., two side walls 24. The bottomface 22 is formed with an auxiliary bore 27 configured for receivingtherein the auxiliary securing bolt 80 to facilitate fastening the baseplate 30 to the bottom face within the insert seat space 20, and a mainbore 25 configured for receiving therein the securing bolt 70 tofacilitate fastening the cutting insert 50 to the bottom face within theinsert seat space.

The tool holder 20 is further formed with an cooling inlet 26 configuredfor emitting the cooling fluid provided through the channel 16, and anoutlet 28 configured for removal of the cooling fluid from the area ofthe insert seat space 20.

As illustrated in FIGS. 3 and 4, the base plate 30 comprises a main body32 having a top face 32 _(T), a bottom face 32 _(B) and side faces 32_(S) extending therebetween. The main body 32 comprises a main bore 35for passing therethrough of the main securing bolt 70 and an auxiliarybore 37 for passing therethrough of the auxiliary securing bolt 80.

The base plate 30 further comprises an inlet hole 36 and an outlet hole38 which, when the base plate 30 is mounted into the insert seat space20 of the cutting tool holder 10, are aligned with the respective inletand outlet 26, 28 of the cutting tool holder 10.

The base plate 30 further comprises a fluid ramp 40 projecting from thetop surface 32 _(T) thereof, disposed between the inlet 36 and theoutlet 38, and configured for directing the flow of the cooling fluidtowards a designated area of the cutting insert 50.

In particular, as shown in FIG. 4, cooling fluid incoming through thechannel 16 is emitted through the inlet 26 and immediately through inlet36. As will be explained in detail later with respect to FIG. 6, fluidflow is restricted by the geometry of the cutting insert 50 and isdirected towards the outlet 38 and subsequently 28 to be emitted fromthe cutting tool 1.

Attention is now drawn to FIGS. 5A and 5B in which a cutting insert 50is shown, comprising a body 52 with a top surface 52 _(T), bottomsurface 52 _(B) and side surfaces 52 _(S) extending therebetween. Thecutting insert 50 has four cutting edges 54 defined at the respectivefour corners of the insert at the intersection between the top surface52 _(T) and the side surfaces 52 _(S). Each cutting edge 54 is delimitedby a rake surface 56 and a relief surface 58 located on opposite sidesof the cutting edge 54. The cutting edge 54, rake surface 56 and reliefsurface 58 constitute together the external surface of the cutting zoneof the cutting insert 50.

In addition, the cutting insert 50 comprises four cooling cavities 60,each associated with a respective cutting edge 54. Each cooling cavityhas an inner space 62 delimited by side walls and a slope 64, taperingaway from the cutting edge 54. The inner surface of the cavity provideseach cutting corner of the cutting insert 50 with a shell-like geometry(a thin-walled structure) which has an external, operational surface(comprising the cutting edge 54) and an internal, cooling surfaceconstituted by the surface of the cavity 60.

It is observed that the cooling surface is formed with an array of ribs,including rake ribs 66 which extend generally parallel to the rakesurface 56 and relief ribs 68 which extend generally parallel to therelief surface 58. With particular reference to FIG. 5B, the rib arrayallows the shell-like geometry to be of relatively small thickness t,reaching extremely close to the cutting edge 54. In other words, thearrangement is such that the cavity surface at the cutting zone is muchcloser to the cutting edge 54 than to the bottom surface 52 _(B) of thecutting insert 50.

It will be appreciated that a cutting insert 20 may comprise a singlerib, which may be a rake rib 66 or relief rib 68 such as described, or asingle rib a portion of which is generally parallel to the rake surface56, and a portion of which is generally parallel to the relief surface58. The single rib may be disposed centrally within the cavity 60, oroff-center.

Turning to FIG. 6, a section of the cutting tool 1 is shown,demonstrating how the cutting insert 50 is positioned on the base plate30. It is observed that since the cavities 60 are only at the vicinityof the cutting corners, the majority of the bottom surface 52 _(B) ofthe cutting insert 50 rests on the base plate 30 and thus providessufficient stability and support to the cutting insert 50.

It is also noted that the geometry of ribs (as opposed to a straightwall) provides for a much stronger construction, allowing the cavity 60to be even closer to the cutting edge 54, i.e., provide a smallerthickness between the external, operative surface and internal, coolingsurface (as small as 0.5 mm).

In operation, during cutting of a workpiece (not shown), the cuttingedge 54 heats up due to constant friction with the workpiece. This heat,reduction of which is usually facilitated by providing a cooling fluiddirectly to the cutting edge, propagates towards the center of thecutting insert 50 so that the body 52 of the cutting insert 50 becomes aheat accumulator.

In order to mitigate this effect, the arrangement according to thesubject matter of the present application allows cooling the innerportion of the cutting zone of the cutting insert 50 therebyfacilitating both increased cooling of the cutting edge 54 (externalcooling is used anyway, though not shown here) and cooling of the body52 of cutting insert 50 itself.

With additional reference being made to FIG. 4, in operation, coolingfluid W is provided to the insert seat space 20. Reaching the insertseat space 20 (position W₂), the cooling fluid is emitted from the inlet36 and is urged into the cavity 60 of the cutting insert 50. There(position W₃), the slope 64 and a ramp 44 define together a graduallytapering channel, with a gradually reducing cross-sectional area, inwhich the velocity of the cooling fluid is increased. The cooling fluidis thus pushed towards the inner surface of the cutting edge 54, inbetween the ribs 66, 68 which maximize heat dissipation between thecutting edge 54 and the cooling fluid W by increasing surface area. Thecooling fluid W is then emitted (position W₄) from the cutting insert 50through the open end of the cavity 60 and is discharged from the cuttingtool holder 10 via inlets 36 and 26 respectively.

The above described cutting insert 50 is configured for both milling andcutting, or turning, operations. In this regards, the followingdifferences should be noted between these two operations:

Milling—

the cutting edge keeps coming in and out of contact with the workpiece.As a result, when it is in contact with the workpiece the cutting edgeheats up, whereas when it is out of contact, the cutting edge coolsdown. However, this constant motion in and out of the workpiece causesthe milling insert to be repeatedly “impacted” by the workpiece,requiring sufficient mechanical robustness and stability;

Turning—

the cutting edge remains within the workpiece throughout the cuttingoperation, whereby the effect of “impact” by the workpiece, which occursin milling, is eliminated. However, since the cutting edge is constantlyin contact with the workpiece, it constantly heats up, requiringsufficient cooling to prevent mechanical damage to the cutting insert.

The above described cutting insert 50 provides both for sufficientmechanical integrity to withstand a milling operation as well assufficient heat removal space for the cooling fluid.

Turning now to FIGS. 7A and 7B, the cutting insert 50 is manufactured ina press mold 100 comprising a female part 110 and a male part 130. Themale part 130 comprises a body 132 formed on a surface thereof with fourprojections 140 which correspond in shape and size to the requiredcavities 60 to be formed within the cutting insert 50. Each projection140 comprises a body 142 formed with a ramp portion 144, rake ribs 146and relief ribs 148.

Attention is now drawn to FIGS. 8A to 8C, in which a variation of theabove cutting tool is shown, generally designated as 1′. Similardesignation numbers have been used with the addition of a prime (′),i.e., cutting tool holder 10′ is equivalent to cutting tool holder 10and so on.

The only difference between the cutting tool 1′ and cutting tool 1 liesin that the outlets 28′, 38′ of the cutting tool holder 10′ and baseplate 30′ respectively, are in the shape of open channels.

Specifically, the heated cooling fluid emitted from the cavity 60′ ofthe cutting insert 50′ does not pass through a closed channel as shownin cutting tool 1, but rather through an open channel 38′, 28′ as shownin the above FIGS.

The open channel configuration allows increasing the flow rate of thecooling fluid W by increasing the drainage rate of the cooling fluid.

Turning now to FIGS. 9A and 9B, another example of a cutting tool isshown, generally designated 1″, and comprising a cutting tool holder10″, a base plate 30″, a cutting insert 50″ and securing bolts 70″, 80″.

In the present example, the insert seat space 20″ of the cutting toolholder 10″ comprises one inlet 26″ located at the proximity of theworking corner and two outlets 28″ located spaced therefrom.

Respectively, the base plate 30″ comprises an inlet 36″ configured to bealigned with the inlet 26″ and two outlets 38″ spaced therefrom andconfigured for being aligned with the outlets 28″. Contrary to thepreviously described example, the base plate 30″ does not comprise afluid ramp.

Turning to FIG. 10, the cutting insert 50″ comprises a main body 52″with a top surface 52 _(T)″, a bottom surface 52 _(B)″ and side surfaces52 _(S)″ extending therebetween. However, whereas in the previousexamples the cavities 60 were individual for each cutting corner, in thepresent example, the cutting insert 50″ has a main cavity 60″, so thatthe entire cutting insert is shell-like (i.e., in the form of athin-walled structure).

Reverting to FIGS. 9C and 9D, under the above configuration, coolingfluid W is provided through an internal channel 16″ (position W₁) and isurged towards the insert seat space 20″. There, the cooling fluid entersthrough the inlets 26″, 36″ (position W₂) and is emitted into the cavity60″ of the cutting insert 50″ and spreads sideways (position W₃),filling the entire cavity 60″. The cooling fluid W is then emittedthrough the discharge outlets 38″ and away from the cutting tool 1″.

It is observed that, as opposed to the previously described example, thecutting insert 50″ of the present example comprises much less material,and is therefore less robust. As a result, it may be that the abovecutting insert 50″ is more suitable for turning operation rather thanmilling.

However, it is noted that the above cutting insert may also be used inmilling, in particular, in milling operations in which three corners ofthe cutting insert 50″ come into contact with the workpiece. In thiscase, it is appreciated that the cooling fluid W facilitates cooling notonly of the main corner towards which the fluid is discharged but alsoto the adjacent cutting corners due to flow of the cooling fluid towardsthe discharge outlets 38″.

Attention is now drawn to FIG. 12, in which another example of a cuttingtool is shown, generally designated 1′″. This tool is generally similarto previously described tool 1″ with the difference being in twofeatures:

Reduced Corner—

the cutting insert 50′″ has a chipped-away portion 59′″ at each cornerproximal to the bottom surface 52 _(B)′″, which provides an additionaldrainage outlet for the cooling fluid during operation, via a formed gapg; and

Additional Holes—

the top surface 52 _(T)′″ of the cutting insert 50′″ is provided withfour through going drainage holes 57′″ which are configured forfacilitating greater removal of cooling fluid from the cutting insert50′″.

It is noted that the drainage holes 57′″ are not directed to the cuttingcorner as they are not intended for providing cooling fluid to theexternal surface of the cutting edge 54′″. On the contrary—the drainageholes 57′″ are only configured for allowing increased evacuation ofcooling fluid from the cutting insert 50′″. Thus, it can be posited thatthe majority of the cooling fluid emitted from the drainage holes 57′″does not reach the operative cutting corner at all.

Turning to FIG. 14, a male part 130′″ is shown constituting part of amold (not shown) for the manufacture of the cutting insert 50′″. It isnoted that the male part 130′″ comprises four corner projections 140′″,each being formed with a hole 147′″ configured for receiving therein acorresponding projection from the female part (not shown) in order toform the drainage holes 57′″.

The male part 130′″ also comprises eight mid-projections 150′″ which areconfigured for the forming of the ribs disposed along the side of thecutting insert 50′″, between two neighboring corners.

Turning now to FIG. 15A, a milling tool is shown, generally designatedas 201 and comprising a tool holder 210 formed with a plurality ofinsert seat spaces 220, each being configured for receiving therein acutting or milling insert 250.

With particular reference being made to FIGS. 15B and 15C, each insertseat space 220 comprises a securing bore 225 configured for receivingtherein a securing bolt 270 for fixing the cutting insert 250 into theinsert seat space 220.

In addition, each insert seat space 220 comprises an inlet 226configured for provisional cooling fluid into the insert seat space 220and an outlet 228 configured for removal of cooling fluid therefrom. Asopposed to the cutting tool 1 previously described, in this case thereis no base plate 30, and the insert seat space 220 itself serves as abase plate.

Thus, the seat surface 222 is formed with a ramp element 240 projectingfrom the insert seat space 220 and has a body 242 with a ramp surface244, an inlet channel 246 and an outlet channel 248 merging withrespective inlet and outlet 226, 228. It is also noted that the outlet228 extends along the insert seat space 220 and has a discharge opening229 at the rear side of the insert seat space 220, the purpose of whichwill not be explained.

Turning to FIG. 15D, when the cutting insert 250 is mounted onto theinsert seat space 220, a configuration similar to that shown in FIG. 1Ais achieved. Thus, during operation, cooling fluid W passes through thetool holder 210, enters the insert seat space 220 via the inlet 226 andis discharged into the cavity 260 of the cutting insert 250. From there,owing to the ramp 240 and slope 264, the fluid is directed to the outlet228.

In this case, the cooling fluid is discharged from the insert seat space220 via discharge opening 229. It is noted here that the dischargeopening 229 is arranged such the discharged fluid is aimed at thecutting corner of the subsequent cutting insert 250, so it also servesas an addition to the standard external cooling. However, it is notedthat the cooling fluid passing through the insert seat space 220 is notused for external cooling of the cutting edge of the cutting insertmounted into that insert seat space.

Reference is now made to FIGS. 16A and 16B, in which a cutting ormilling insert 250 is shown. In principle, the milling insert 250 isgenerally similar to the cutting insert 50 previously described with thedifference being it has two cutting corners and two correspondingcavities 260.

With reference to FIGS. 17A, 17B, the milling insert 250 is manufacturedin a pressing process within a mold 300 comprising a male part 330 and afemale part 310.

With regards to all of the above cutting inserts 50, 50, 50, 50′″ and250—all can be manufactured in a pressing/sintering process, allowingfor convenient mass production of the cutting inserts.

Attention is now drawn to FIGS. 18A to 20C, in which another example ofa cutting tool is shown, generally designated 401, and a mold for themanufacture of its cutting insert 450.

As seen in FIGS. 18B and 18C, the cutting insert 450 comprises an insertbore 455 which is diagonally oriented with respect to the top and bottomsurfaces 452 _(T), 452 _(E) respectively.

Such an orientation of the insert bore allows forming the coolingcavities 460 closer to the cutting edge 454, since the diagonalorientation leaves more material area to be worked with. This, in turn,allows for a more robust structure of the cutting insert, the mechanicalintegrity of which is not greatly deteriorated due to the forming of thecooling cavity 460.

It is observed that the cooling cavity 460 is of conical shape spanningbetween an open bottom end 460 _(B) and a top end 460 _(T), facilitatingconcentrating the flow of cooling fluid therewithin towards an area ofthe cutting insert 450 directly adjacent and behind the cutting edge 454(the flow being designated by arrows 428). In particular, for example asbest seen in FIG. 19, a front side of a wall 461 defining each of thecavities 460 is disposed such that at least a portion thereof (e.g., atleast that portion adjacent the bottom end 460 _(B)) forms an angle αwith respect to the bottom surface 452 _(B), in a direction toward therelief surface 458, which is less than 90°, i.e., the top end 460 _(T)of each cavity 460 is disposed farther forward (i.e., toward the cuttingedge/relief surface) than is any part of the bottom end 460 _(B).

It will be appreciated that owing to the disposition of the top end 460_(T) of each cooling cavity 460 forward of the open bottom end 460 _(B)thereof, a portion of the cavity is above material of the cutting insert450 (i.e., a straight path perpendicular from the bottom surface 452_(B) to at least some of the cavity passes through material of theinsert; along an axis parallel to the top and bottom surfaces 452 _(T),452 _(B), the top end 460 _(T) of the cooling cavity 460 is closer tothe respective cutting edge than is any part of the open bottom end 460_(B)). Accordingly, a molding process to manufacture the cutting insert450 must be performed so as to produce it at an angle, as will bedescribed below.

The geometry of the cooling cavity 460 therefore defines one or more(e.g., a range) molding angles, with respect to the bottom surface 452_(B), along which a solid element having the shape of the cooling cavityand completely inserted therein (such as part of a mold) may beretracted therefrom along a linear path. Accordingly, the cutting insert450 is associated with a molding axis M (for example as indicated inFIG. 18D), which is oriented along one of the angles defined by thecooling cavities 460. According to some examples, the molding axis M isdisposed at an angle of 45° with respect to the bottom surface 452 _(B),for example within a plane bisecting the cutting edge 454.

As illustrated in FIGS. 18D-18G, side surface 452 _(S) of the cuttinginsert, spanning between the top and bottom surfaces 452 _(T), 452 _(B),comprise a circumscribing portion 462, constituted by segments 462 athrough 462 h, and demarcated by first and second edges 463 a, 463 b(for clarity, only some of the first and second edges are indicated; itwill be appreciated that some of the edges 463 a, 463 b may be formedbetween the circumscribing portion 462 and one of the top and bottomsurfaces 452 _(T), 452 _(B), the side surface 452 _(S), or a combinationthereof). The circumscribing portion 462 is, along its entire extent,parallel to the molding axis M, i.e., in any plane in which the moldingaxis lies, an intersection line between the plane and the circumscribingportion is parallel to the molding axis.

The circumscribing portion 462 has a non-zero height, in a directionparallel to the molding axis M, along its entire extent (i.e., theentire way around the circumscribing portion). The significance of thenon-zero height will be explained below with respect to the moldingprocess; it will be understood that such explanation will inform onehaving skill in the art the scope of the term “non-zero height” in thepresently disclosed subject matter and appended claims. As illustrated,the height of the circumscribing portion 462 may vary along its extendaround the cutting insert 450), or it may be constant thereabout.

Furthermore, the cutting insert 450 does not extend beyond thecircumscribing portion 462, i.e., in any plane in which the molding axislies, there is no material of the cutting insert beyond thecircumscribing portion. Accordingly, for example as best seen in FIG.18E, in a plan view perpendicular to the molding axis M, thecircumscribing portion 462 defines the outer perimeter of the cuttinginsert 450.

As seen for example in FIGS. 18C and 18D, at least one of the sidesurfaces 452 _(S) is formed with a shelf 459 extending therealong. Theshelf 459 is disposed transverse to the molding axis M, for exampleperpendicular thereto. The area above the shelf 459 is free of materialof the cutting insert 450, i.e., for each point of the shelf 459, a pathextending thereabove (i.e., in the direction in which the shelf faces)and which is parallel to the molding axis M does not contain anymaterial of the cutting insert.

The shelf 459 may be formed such that it generally faces (i.e., it isdisposed so as to face the general direction of) either the top surface452 _(T) or the bottom surface 452 _(B). It will be appreciated thatwhile the cutting insert 450 is described herein with reference to andillustrated in the accompanying figures as being formed with shelves 459on two of its sidewalls 452 _(S), and in particular two adjacentsidewalls between which one of the cooling cavities 460 is disposed, acutting insert 450 may be provided according to the presently disclosedsubject matter having one or more shelves as described above withreference to and as illustrated in the accompanying drawings beingformed on fewer or more of the sidewalls, including, but not limited to,on all of the sidewalls, mutatis mutandis.

Turning now to FIGS. 20A to 20C, a mold 501 for the manufacture of thecutting insert 450 is shown, comprising a female mold portion 510 and amale portion 530. The female mold portion 510 comprises parallellyextending sidewalls 511 and an open top end 513 defining therebetween acavity 515, and a upwardly-facing first imprinting surface 517 adisposed at the bottom of the cavity. The male mold portion 530 isconfigured to be snuggly received within the cavity 515 of the femalemold portion 510 and slidable along longitudinal axis X of the mold 501,and comprises a downwardly-facing second imprinting surface 517 b on abottom side thereof.

Each of the imprinting surfaces 517 a, 517 b has a shape whichcorresponds to that of a respective part of the cutting insert 450 whenit is oriented such that its molding axis M is parallel to the sidewalls511 of the female mold portion 510, each of the parts being demarcatedby one of the edges 463 a, 463 b of the circumscribing portion 462. Inparticular, each of the imprinting surfaces 517 a, 517 b comprises aprotrusion 540 corresponding to a respective cooling cavity 460.Accordingly, when the cutting insert 450 is produced within the mold501, the circumscribing portion 462 is defined by the portion of thesidewalls 511 of the female mold portion 510 between the first andsecond imprinting surfaces 517 a, 517 b, i.e., it is formed abuttingthem. Thus, the cavity 515, when the first and second imprintingsurfaces 517 a, 517 b are suitably spaced from one another, has theshape of the cutting insert 450 described above with reference to andillustrated in FIGS. 18A-18G. As best seen in FIG. 20B, one or both ofthe imprinting surfaces 517 a, 517 b may be formed with one or moreledges 550, which are configured to form the shelf 459 described above.

It will be appreciated that the cutting insert 450 is produced by themold 501 oriented such that its molding axis M is parallel to thelongitudinal axis X of the mold 501, i.e., the top and bottom surfaces452 _(T), 452 _(E) of the cutting insert are oriented) at an angle withrespect to the longitudinal axis X of the mold (the axis along which themold portions 510, 530 are displaced when pressing) corresponding to themolding angle M. This permits the protrusions 540 to be withdrawn fromtheir respective cooling cavities 460 without being damaged or causingdamage to the cutting insert 450. As a result, the cooling cavities 460,which are formed generally along the longitudinal axis, are eventuallyangled to the cutting edge 454 of the cutting insert 450 at the desiredangle.

It is important to note that while the pressing is performed along apressing axis which extends generally along the longitudinal directionof the male and female member, the operative surfaces of the latter, theones used to form the top and bottom surfaces of the cutting insert areangled at 450 to the pressing axis, allowing the forming of the cavityat the desired angle.

As illustrated in FIG. 20D, there is provided a method 570 for producinga cutting insert 450, for example as described above with reference toand illustrated in FIGS. 19A-18G, using a mold 501.

In a first step 571 of the method 570, a mold 501, for example asdescribed above with reference to and illustrated in FIGS. 20A-20C, isprovided.

In a second step 572 of the method 570, raw material is provided in thecavity 515 of the female mold portion 510 of the mold 501. The amount ofraw material is suitable for forming one cutting insert 450, i.e., itsvolume after the molding process is equal to that of the cutting insert.

In a third step 573 of the method 570, the male mold portion 530 isinserted into the cavity 515, such that the first and second imprintingsurfaces 517 a, 517 b face one another.

In a fourth step 574 of the method 570, the cutting insert 450 isformed, in the space of the cavity 515 between the first and secondimprinting surfaces 517 a, 517 b, from the raw material.

It will be appreciated that during molding of the cutting insert 450,the first and second imprinting surfaces 517 a, 517 b are spaced fromone another, which gives rise to the non-zero height of thecircumscribing portion 462. Accordingly, molding the cutting insert 450having a circumscribing portion 462 as described above with a non-zeroheight, allows the female and male mold portions 510, 530 to be pressedtoward one another without contacting each other, which could result indamage thereto. Similarly, the shelf 459 further facilitates pressingthe female and male mold portions 510, 530 toward one another withoutcontacting one another.

The raw material provided in the second step 572 may be any suitablematerial, and the forming of the fourth step 574 may be by any processsuitable to the raw material. According to some examples, the rawmaterial is a sintering material, for example comprising a ceramicpowder, and the forming comprises providing suitable pressure forsintering. According to other examples, the raw material comprises oneor more metals, for example provided in liquid form, and the formingcomprises allowing the raw material to solidify, e.g., by cooling.

Turning now to FIGS. 21A to 22D, there is provided another example of acutting tool designated 601, and comprising a cutting insert 650 mountedon a tool holder 610. Similar to the previous example, the cuttinginsert 650 is formed with two opposite cutting edges 654, eachcomprising a cooling cavity angled to the top surface at 45°.

Similar elements have been designated with similar reference numbers,with the addition of 600 (i.e., cutting insert 650 uses a similarreference number as cutting insert 450, both having cutting edge 454,654 etc.)

However, contrary to the previous example, the cutting insert 650comprises two portions which are angled to one another at 1350, yieldingthat the cooling cavities 660 are generally parallel to one another.

This provides a very important advantage with respect to the pressingprocess. In particular, contrary to the previous example which requiredforming the cutting insert 450 at an orientation angled to the pressingaxis, in this example, the cutting insert 650 can be formedsymmetrically with the pressing axis as the projections forming thecooling cavities 660 extend generally along the pressing axis.

The above yields an angled configuration of the cutting insert itself650, in this particular example, each portion of the cutting insert isof a triangular shape, the portions being angled to one another, asshown in FIG. 22B.

In addition, with particular reference being made to FIG. 23, it isnoted that the cutting insert, when mounted onto the cutting tool holder610, is supported by three different surface—a base surface provided byan intermediary plate 630 and two side surfaces 624 of the cutting toolholder 610. It is noted that the bottom surface of the other portion ofthe cutting insert 650, does not come into contact with a base surfaceof the holder 610, as shown by the gap E.

Reverting back to FIGS. 22A to 22D, the cutting insert 650 is shown tohave an additional flow outlet 657 at the top surface of the cuttinginsert, and is provided with a flow channel 659 configured for directingthe flow of the cooling fluid towards the cutting edge 654. It is alsonoted that the outlet 657 is located below the top surface 652 _(T) ofthe cutting insert 650.

The flow channel 659 merges with the chip breaking channel 656 of thecutting insert 650, allowing fluid flow to reach very close to thecutting edge 654 and, at the same time, lift chips removed from theworkpiece during a cutting operation.

Attention is now drawn to FIGS. 25A to 27, in which another example of acutting tool is shown, generally designated 601′, which is generallysimilar to the previously described cutting tool 601. Similar elementshave been designated with similar reference numbers, with the additionof a prime (i.e., cutting insert 650 uses a similar reference number ascutting insert 650′, both having cutting edge 654, 654′ etc.).

The main differences between the cutting tool 601′ and 601 are asfollows:

First of all, the holder 610′ is designed with an additional flowchannel 618′ and 619′ (FIG. 25C) which is configured for recyclingcooling fluid used previously for cooling the cutting edge 654′ back tothe holder so that it is ejected therefrom to impinge on the reliefsurface of the cutting insert 650′ as shown in FIG. 25C.

Secondly, the flow channel 659′ is provided with a blocker 651′ which isconfigured for preventing chips removed from the workpiece by thecutting edge 654′ from flowing towards the outlet 657′ and blocking it.On the other hand, the blocker 651′ has a stream-line design configuredfor minimally obstructing cooling fluid emitted from the outlet 657′towards the cutting edge 654′ (see FIG. 27).

Contrary to the previously described example 601, the cutting insert650′ further comprises supports 690 in the form of triangularprojections 692′ and 694′, configured for being received with the holder610′. The arrangement of the supports 692′, 694′ is such that allows thecutting insert 650′ more surface contact with the holder 610′ (comparedto the example 601).

Since the bottom surface of the other portion of the cutting insert (theone that, at a given moment, does not perform a cutting operation) isnot mated against a base surface of the holder 610′, the supports 692′,694′ allow preventing a see-saw motion of the cutting insert which couldlead to disengagement between the bottom surface 652 _(B)′ of theoperational cutting portion and the plate 630′.

Attention is now drawn to FIGS. 28 to 29B, in which yet another exampleof a cutting tool is shown, generally designated 601″. Similar elementshave been designated with similar reference numbers, with the additionof a double prime (i.e., cutting insert 650 uses a similar referencenumber as cutting insert 650″, both having cutting edge 654, 654″ etc.).

The main difference between the cutting insert 650″ and the previouslydescribed cutting insert 650′ lies in the design of the bottom surfaceof the cutting insert, 652 _(B)″. Whereas the previous cutting insert650′ was shown to have a see-saw configuration, the cutting insert 650″has a flat bottom surface 652 _(B)″.

With particular reference being made to FIG. 29B, it is noted that whencomparing the geometry of the cutting insert 650′ and 650″, the materialremoved from the tip of the see-saw of cutting insert 650′, iscompensated by addition of material at the sides in cutting insert 650″.

Attention is now drawn to FIGS. 30A to 31C, in which still anotherexample of a cutting tool is shown, generally designated 610′″. Similarelements have been designated with similar reference numbers, with theaddition of a triple prime (i.e., cutting insert 650 uses a similarreference number as cutting insert 650′″, both having cutting edge 654,654′″ etc.).

The main difference between the cutting tool 601′″ and the cutting tool601″ lies in the fastening mechanism used to secure the cutting insert650′″ to the tool holder 610′″. In particular, a clamping mechanism 700is used, which operates in conjunction with a recess 635′″ of thecutting insert 650′″, contrary to an insert bore as described withrespect to the previous examples.

Turning now to FIGS. 32 to 33C, another example of a cutting tool isshown, generally designated 801, and comprising a cutting insert 850mounted onto a cutting tool holder 810.

Similar elements have been designated with similar reference numbers,with the addition of 800 (i.e., cutting insert 850 uses a similarreference number as cutting insert 650, both having cutting edge 654,854 etc.).

The cutting insert 850 is formed with openings along the circumferencethereof configured for allowing cooling fluid to flow therein and reachthe entire length of the cutting edge 854 of the cutting insert 850.

Cooling fluid is provided through the cutting tool holder 810 andintermediate plate 830, and emitted from outlets O (see FIG. 32). Thecooling fluid emitted therefrom spreads along the hollow bottom ofcutting insert 850 and is later emitted therefrom through the arcuateopenings 860 a, 860 b, 860 c.

It is noted that the wall of the openings are arranged so as to face thecutting corner of the cutting insert 850 (rather than beingperpendicular to the side surfaces 852 _(S) of the cutting insert 850).

Turning now to FIGS. 34A to 36E, a milling tool is shown, generallydesignated 901 and comprising a cutting tool holder 910 and a pluralityof cutting, or milling, inserts 950. The cutting inserts 950 are similarto cutting inserts 650″ previously described, i.e., having a see-sawconfiguration (see FIG. 36E).

In addition, as shown in FIG. 34B, cooling fluid used for internalcooling of the milling inserts 950 is redirected, after removing heatfrom the internal side opposite the cutting edge, to two directions:

A first portion of the cooling fluid is directed, similar to cuttingtool 601′, back towards the relief surface of the cutting insert 950 viaoutlet 919 b.

A second portion of the cooling fluid is directed backwards to impactthe cutting edge of the subsequent milling insert 950, via outlets 918b.

In this manner, cooling fluid usage is somewhat optimized to remove heatnot only from the cutting insert to which it is originally directed butfrom a subsequent cutting insert as well. It is appreciated that thesubsequent cutting insert has a cooling mechanism of its own and that aportion of the cooling fluid used therein is directed to a cuttinginsert subsequent thereto and so on, and so forth.

Attention is now brought to FIGS. 37A to 38, in which a drilling tool isshown, generally designated 1101, comprising a tool holder 1110 and acutting, or drilling, insert 1150. Similar elements have been designatedwith similar reference numbers, with the addition of 1000 (i.e., cuttinginsert 1150 uses a similar reference number as cutting insert 650, bothhaving cutting edge 654, 1154 etc.).

In the example described herein, as in previous examples, the coolingcavity 1136 almost reaches the cutting edge 1154 of the drilling tool1101, allowing to provide cooling fluid directly to the cutting edge1154.

However, due to the geometry of the drilling tool 1101 (see FIG. 38, thecooling fluid provided thereto ends up at a “dead-end” in terms of flow.In order to remove cooling fluid from such a dead-end and allowing newcooling fluid to flow in and replace it, the drilling tool 1101 makesuse of its own spinning and interaction with the workpiece.

In particular, when the drilling tool 1101 revolves with respect to theworkpiece, the bottom surface of the bore formed in the workpiececonstantly carries away with it, during respective turning of thedrilling tool, the cooling fluid “stuck” at the dead-end and removes itfrom the area. This also allows breaking up the boundary layers at thefront surface of the drill, allowing for more efficient cooling andfluid flow.

With particular reference to FIG. 38, the chamfered surface indicated byarrow R does not come into contact with the workpiece, allowing coolingfluid to flow away from the cutting edge as it is removed from thecutting area.

It will be appreciated that while examples described herein withreference to and as illustrated in the accompanying drawing relate to acutting insert, this is by way of illustrating a non-limiting exampleonly, and are not to be construed as limiting to a cutting insert. Theteachings of this disclosure may be applied to any suitable cuttingelement, and cutting elements provided in accordance with the teachingsof this disclosure are included within the scope of the presentlydisclosed subject matter, mutatis mutandis.

Those skilled in the art to which this invention pertains will readilyappreciate that numerous changes, variations, and modifications can bemade without departing from the scope of the invention, mutatismutandis.

The invention claimed is:
 1. A cutting insert, comprising: an insertbody manufactured in a press mold and having a front face, an oppositerear face, and side faces extending therebetween; a rake surfaceconstituted by a portion of the front face; a relief surface constitutedby a portion of one of the side faces; a cutting edge defined at anintersection of the rake surface and relief surfaces; a cooling cavityformed within said insert body, defined by a cavity surface delimited byside walls and a slope, tapering away from the cutting edge and having acurved front surface portion disposed closer to the front face of theinsert than to the rear face of the insert; the cavity extending fromsaid curved front surface portion towards the rear face of the cuttinginsert along the slope; and at least one shell-like cutting zone definedby an external surface and an internal surface, the external surfacebeing constituted by the cutting edge and the corresponding rake andrelief surfaces, the internal surface being at least partially definedby said curved front surface portion and the slope of the cavity surfaceso as to allow cooling of the at least one shell-like cutting zone byfluid directed thereto along the slope of the cavity surface towardssaid curved front surface portion.
 2. The cutting insert according toclaim 1, wherein, in a plane perpendicular to the front and rear facesand passing through the cutting edge, the cooling cavity ischaracterized by first and second dimensions, the first dimension beingadjacent the rear face, and the second dimension being adjacent thecurved front surface portion, the first dimension being larger than thesecond dimension.
 3. The cutting insert according to claim 2, whereinthe second dimension is along a line passing through the at least oneshell-like cutting zone at its narrowest region between the reliefsurface and the internal surface.
 4. The cutting insert according toclaim 2, wherein the second dimension is along a line passing throughthe at least one shell-like cutting zone at its narrowest point betweenthe rake surface and the internal surface.
 5. The cutting insertaccording to claim 1, wherein said cooling cavity has at least one fluidentrance area and at least one fluid exit area both open to the exteriorof the insert and spaced from each other so as to allow fluid enteringthe fluid entrance area to pass in contact with the cavity surfaceincluding the curved surface portion, to the fluid exit area.
 6. Thecutting insert according to claim 5, wherein the cavity surface isformed with at least one rib protruding into the cavity, the rib beingseen via at least one of the fluid entrance area and fluid exit area ina rear view of the insert.
 7. The cutting insert according to claim 5,wherein the cavity surface of the cooling cavity continuously convergesfrom the fluid entrance area and the fluid exit area towards the curvedsurface portion.
 8. The cutting insert according to claim 5, wherein theinternal surface of the at least one shell-like cutting zone consists ofthe curved surface portion which is configured for directing the coolingfluid reaching said portion from the fluid entrance area toward thefluid exit area for being emitted therefrom.
 9. The cutting insertaccording to claim 5, wherein the fluid entrance and fluid exit areasconstitute respective fluid entrance and fluid exit portions of an openend of the cooling cavity, opposite the curved surface portion,configured for receiving therein, via the fluid entrance portion, acooling fluid to cool the at least one shell-like cutting zone and towithdraw heat from the cutting edge, and being further configured fordirecting the cooling fluid toward the fluid exit portion for beingemitted therefrom.
 10. The cutting insert according to claim 5, whereinthe at least one fluid entrance area and the at least one fluid exitarea are disposed at the rear face of the cutting insert and are spacedfrom each other therealong.
 11. The cutting insert according to claim 1,wherein the cavity surface is formed with at least one rib protrudinginto the cavity.
 12. The cutting insert according to claim 1, whereinthe curved front surface portion of the cavity surface continuouslyconverges at least toward the rake surface.
 13. The cutting insertaccording to claim 1, wherein the cavity surface of the cooling cavitycontinuously converges at least toward the rake surface.
 14. The cuttinginsert according to claim 1, wherein a smallest distance between thecurved front surface portion of the cavity surface and the cutting edgeis larger than each of a smallest distance between said portion and therelief surface and a smallest distance between said portion and the rakesurface.
 15. The cutting insert according to claim 1, wherein the curvedsurface portion is concaved.
 16. The cutting insert according to claim1, being configured for a turning operation.
 17. The cutting insertaccording to claim 1, being configured for a drilling operation.
 18. Thecutting insert according to claim 1, being configured for a millingoperation.